Core A measures serum, serum ultrafiltrate (UF), plasma and urine stone risk chemistries and calculates urine supersaturations (SS) for patients studied in Projects 1 and 2. These measurements are used for fulfillment of aims within all three projects and six program aims carried out within the overall program project. Plasma GLP-1, renin, and plasma and urine cAMP will also be measured by Core A for Project 1. Blood and urine samples are processed and shipped for assay of lithium done in Core B and for measurement of plasma glucagon, parathyroid hormone (PTH) and 1,25 vitamin D (performed by LabCorp). Sample aliquots are stored at -80C for future use. All laboratory data from Core A for all projects are consolidated into a single database with daily backup for security and ease of analysis. Ultimately, data from the other projects and cores (e.g. histology, biopsy, stone analysis etc.) will be consolidated into our database so that it can be analyzed along with serum and urine data.